In the manufacture of batting, natural or synthetic fibers making up the batting are fed through a series of carding or garnetting units which comb the fibers before depositing the fibers onto a traveling belt where the fibers are accumulated and matted together to form a thick web which is transported to another location for use in the manufacture of cushions, upholstery, pillows, mattresses, pads, and the like. The fabrication of the batting into the various products have presented individual problems, with a number of the processes involved being very labor intensive.
One particular labor intensive process has been the fabrication of cushions for chair or sofa seats and backs, or the like. These cushions must be very firm so as not to bottom-out when compressed, but yet they must have a uniform cushioning feel throughout. In order to obtain the necessary firmness and uniform cushioning feel it has been customary in the trade to take many layers of unbonded batting or one very thick layer of unbonded batting, and stuff the batting into a cushion casing. The process is primarily a hand operation, with resultant high labor costs. Moreover, even with the care possible in a hand operation, the uniformity of the cushion is determined by the individual capability and care of a particular operator, leading to quality control problems.
Heretofore it has been recognized that synthetic fibrous battings can be compressed. Thus, U.S. Pat. Nos. 2,893,105; 2,908,064, and 2,910,763 disclose non-woven filamentary products or the like wherein after the fibers and filaments are carded or garnetted they are needle-punched to densify the batt, and thereafter the batt is subjected to pressing rolls. The process, utilizing select components, is substantially time-consuming and results in a thin compressed web having specific applications. U.S. Pat. Nos. 3,364,543 and 3,407,461 provide compressed battings based on needle-punching and mechanical compression. U.S. Pat. No. 3,936,555 discloses a product having a density gradient from surface to surface. These products are manufactured by needling a batt, impregnating the batt with a liquid-phase filler, and thereafter bonding a plurality of-the batts together. U.S. Pat. No. 4,284,680 discloses a multi-layered needle-punched, felt-like cushioning material. The cushioning material is made up of at least two fibrous batts and at least one foundation fabric interposed between the batts and needle-punched with the batts. U.S. Pat. No. 4,129,675 discloses a batt made of a blend of hollow polyester fibers. The blend is subjected to contact heating such as by passing the batt through a compression zone formed between a heated roller and a conveyor belt, with the heating roll heating and compressing the batt to generally no more than about 50% of its original thickness. It is stated that hollow polyester fibers provide unexpectedly high filling power in a batt as compared to using solid fibers. It is recognized that the heat and compression treatment, depending on the degree of compression, will provide a batt with a scrim or skin at the surface of the batt. It is also stated that the scrim or skin is of a greater opacity and a lesser porosity when using hollow polyester fibers than is obtained from the same treatment except where solid fibers are utilized.
The compressed synthetic battings of the prior art have only a limited thickness. Although it is proposed that these batts can be layered, such layering also causes problems and is not totally satisfactory. Further, the compressed batts conventionally are not thermo-bonded. It was believed that difficulties would be encountered in making thick, thermo-bonded densified batts due to localized heating at the surfaces of the batt, thus providing a batt which has a greater density or skin at the surfaces, precluding uniform characteristics and feel throughout the batt, as noted in U.S. Pat. No. 4,129,675.
Moreover, heretofore when a compressed batting being of small thickness regardless of how made is stuffed into a cushion casing, distinct areas of non-uniformity in the cushioning are realized as a result of air spaces adjacent to the different layers or foldings of the thin densified batting. This provides a product having a degree of non-uniformity. Moreover, when the densified batting is stacked as layers and put into a cushion casing, similar non-uniformity in feel characteristics are observed due to the spacing between the various layers.
Accordingly, there has been a distinct need for a densified batting having a uniformity throughout and in a thickness sufficient to permit a single layer of the batting to be utilized in a cushioning or the like product.